Crowdstrike Ephemeral User Account

Severity: high
Time window: 12h
Match by: p_alert_context.target_name
Source: github.com/panther-labs/panther-analysis

Detects when a user account is created and deleted within 12 hours. This aims to detect ephemeral user accounts infiltrators might use to avoid suspicion.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1136.003` Create Account: Cloud Account
Stealth	`T1070` Indicator Removal

Rule body yaml

AnalysisType: correlation_rule
RuleID: "Crowdstrike.EphemeralUserAccount"
DisplayName: "Crowdstrike Ephemeral User Account"
Enabled: true
Severity: High
Description: Detects when a user account is created and deleted within 12 hours. This aims to detect ephemeral user accounts infiltrators might use to avoid suspicion.
Reference: ""
Reports:
  MITRE ATT&CK:
    - TA0003:T1136.003 # Persistence: Create Cloud Account
    - TA0005:T1070 # Defense Evasion: Indicator Removal
Detection:
  - Sequence:
      - ID: AccountCreated
        RuleID: Crowdstrike.NewUserCreated
      - ID: AccountDeleted
        RuleID: Crowdstrike.UserDeleted
    Transitions:
      - ID: User Created FOLLOWED BY User Deleted
        From: AccountCreated
        To: AccountDeleted
        WithinTimeFrameMinutes: 720 # 12 hours
        Match:
          - On: p_alert_context.target_name
    LookbackWindowMinutes: 2160
    Schedule:
      RateMinutes: 1440
      TimeoutMinutes: 1
Tests:
  - Name: User Creation, Followed By Deletion
    ExpectedResult: true
    RuleOutputs:
      - ID: AccountCreated
        Matches:
          p_alert_context.target_name:
            'non.chalant@legitbiz.com':
              - 0
      - ID: AccountDeleted
        Matches:
          p_alert_context.target_name:
            'non.chalant@legitbiz.com':
              - 640 # 9 hours
  - Name: User Creation, Not Followed By Deletion
    ExpectedResult: false
    RuleOutputs:
      - ID: AccountCreated
        Matches:
          p_alert_context.target_name:
            'non.chalant@legitbiz.com':
              - 0
  - Name: User Deletion, Not Preceded By Creation
    ExpectedResult: false
    RuleOutputs:
      - ID: AccountDeleted
        Matches:
          p_alert_context.target_name:
            'non.chalant@legitbiz.com':
              - 120 # 2 hours

Detection logic

Stage 1: `step AccountCreated` ordered before `$AccountDeleted`

References detection Crowdstrike.NewUserCreated.

Stage 2: `step AccountDeleted` ordered after `$AccountCreated`

References detection Crowdstrike.UserDeleted.

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`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Crowdstrike Ephemeral User Account

MITRE ATT&CK coverage

Rule body yaml

Detection logic

Stage 1: `step AccountCreated` ordered before `$AccountDeleted`

Stage 2: `step AccountDeleted` ordered after `$AccountCreated`

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Search operators

Crowdstrike Ephemeral User Account

MITRE ATT&CK coverage

Rule body yaml

Detection logic

Stage 1: step AccountCreated ordered before $AccountDeleted

Stage 2: step AccountDeleted ordered after $AccountCreated

Stage 1: `step AccountCreated` ordered before `$AccountDeleted`

Stage 2: `step AccountDeleted` ordered after `$AccountCreated`